We plan to continue and expand research and training coincident with the general aspirations of Developmental Biology in Mental Retardation. This project includes studies in etiology and pathogenesis of genetic abnormalities, metabolic disorders, development of experimental procedures, and models of disease which stem from tissue culture preparations of patient tissue samples, cell particulates, aggregate studies of dissociated normal and abnormal brain, electron microscopy, biochemistry, nutritional manipulation effects of drugs, and hormone deficiency and plethora. The general plan is based on an interdisciplinary approach to the various investigations.